Q.

Two long parallel wires carrying currents 8 A and 15 A in opposite directions are placed at a distance of 7 cm from each other. A point P is at equidistant from both the wires such that the lines joining the point P to the wires are perpendicular to each other. The magnitude of magnetic field at P is ________ ×10-6 T. (Given: 2=1.4)     [2023]


Ans.

(68)

Magnetic fields due to both wires will be perpendicular to each other.

B1=μ0i12πd,  B2=μ0i22πd

Bnet=B12+B22=μ02πdi12+i22

4π×10-72π×(72)×10-2×82+152 (d=72 cm)

=68×10-6 T